Only 1 in 8 well-known cities meets the minimum living standards. What does this mean? (Photo included)

The "3+30+300 Rule" serves as a foundation for developing greener, healthier, and more heat-resilient cities, which is particularly crucial in the context of the climate crisis, as the Earth is warming at an unprecedented rate. But how many cities worldwide actually meet even the minimum standards? Scientists have provided an answer, and it is not encouraging, as reported by Science Alert.

This straightforward measure, known as the "3+30+300 Rule," was initially conceived in Europe and is now gaining traction globally. It also establishes a minimum standard necessary to reap health benefits from nature in urban areas.

The "3+30+300 Rule" necessitates:

• the presence of three trees visible from the window of a home, school, or workplace;
• the presence of a tree canopy covering at least 30% of the surrounding area;
• the availability of a park within 300 meters of a building.

According to Tami Krezer, a research fellow at the RMIT University Urban Research Centre, she and her colleagues evaluated the standards set by this rule in eight cities around the world:

• Melbourne;
• Sydney;
• New York;
• Denver;
• Seattle;
• Buenos Aires;
• Amsterdam;
• Singapore.

The results indicate that most buildings do not actually comply with the "3+30+300 Rule." The team found that there is a desperate shortage of trees even in some of the wealthiest and most iconic cities on the planet. Furthermore, scientists believe that our cities are critically lacking in cooling, especially in light of the planet's overheating.

Previous studies have shown that people are more likely to suffer from depression, anxiety, obesity, and heat strokes in areas with fewer trees or limited access to parks. According to Dutch urban forestry expert Professor Cecile Koneinendijk, who established the minimum standard known as the "3+30+300 Rule" in 2022, this criterion is based on an extensive review of evidence linking the natural environment to human well-being.

It is important to note that the "3+30+300 Rule" is still gaining popularity; however, some cities in Europe, the USA, and Canada actively implement this measure, both officially and unofficially.

In a new study, researchers applied the "3+30+300 Rule" to a global list of urban trees, compiling data from open sources provided by local authorities. The authors of the study point out that the eight cities were chosen deliberately, as the scientists aimed to select at least one city from each continent. As a result, they chose eight cities that are considered leaders in urban forestry and green space development.

The findings indicate that most buildings in the eight cities met the requirement of having three trees but failed to achieve the canopy coverage level. Conversely, three out of four (75%) buildings met the 30% canopy coverage standard in Singapore, and nearly half (45%) did so in Seattle. Only 3% of buildings in Melbourne had adequate canopy coverage, even though 44% had a view of at least three trees. Central Sydney performed better, although only 17% of urban buildings were sufficiently shaded, despite 84% having a view of at least three trees. As a result, Singapore became the only city in the world to score high enough.

Researchers also found that access to parks was uneven across cities: Singapore and Amsterdam received good ratings, while Buenos Aires and New York ranked lowest. The researchers mapped the results and were surprised to discover that most buildings worldwide had a view of at least three trees but still lacked adequate canopy coverage for the area. Scientists found that these three trees, however visible, were often too small to provide decent shade. Another issue was planting density—larger trees tended to be too widely spaced.